Process for dyeing animal textile fibers comprising the use of purified synthetic food dyes

Abstract

A textile dyeing process is described for dyeing a textile material, product or article consisting of animal fibers, comprising the steps of dipping said textile material, product or article into a dyeing bath comprising at least one detergent substance, a wetting substance, a leveling substance and an acidity regulator; adding to the dyeing bath a coloring substance approved for food use; subjecting the dyed textile material, product or article to washes; and finally subjecting the dyed textile material, product or article to a color fixing treatment.

The invention claimed is: 
     
       1. A textile dyeing process for dyeing a textile material, product or article of fibers and fabrics consisting of animal hair, comprising the following steps, wherein steps 1) to 5) take place under stirring:
 1) dipping the textile material, product or article for a period between 5 and 15 minutes into a water-based dyeing bath having a temperature between 20 and 30° C., said bath comprising at least:
 2,2-dimethyl-1,3-propanediol (CAS no. 126-30-7) as a detergent substance;
 a wetting substance selected from polyethylene glycol-10 propyl ether ((C 2 H 4 O) n C 10 H 22 O, CAS no. 160875-66-1), petroleum distillate (CAS No. 64742-47-8), undecyl alcohol ethoxylates (CAS No. 127036-24-2) and a mixture of 2-methyl-3(2H)-isothiazolone and 5-chloro-2-methyl-3(2H)-isothiazolone (CAS no. 55965-84-9); 
 
 a leveling substance selected from 5-sulfosalicylic acid (CAS no. 97-05-2), polyethoxylated tallow amines (CAS no. 61791-26-2), quaternary salts of polyethoxylated tallow amines with diethylsulphate (CAS no. 68071-95-4) and a mixture of C16-C18 ethoxylated unsaturated alcohols (CAS no. 68920-66-1); 
 an acidity regulator consisting of a mixture of citric acid (CAS no. 77-92-2) and 5-sulfosalicylic acid (CAS no. 97-05-2), in a weight ratio between citric acid and 5-sulfosalicylic acid between 4:1 and 9:1; 
 
 2) adding to the dyeing bath of step 1 one or more synthetic coloring substances, bringing the bath to a temperature between 80 and 120° C. in a time between 50 and 80 minutes, leaving it at this temperature for a time between 30 and 90 minutes, and finally cooling the bath to a temperature between 60 and 80° C. in a time between 10 and 30 minutes; 
 3) draining the bath and subjecting the textile material, product or article dyed in the previous passages to a first wash in the same machine at a temperature between 35 and 55° C. for a time between 5 and 15 minutes; 
 4) draining the bath of the first wash and subjecting the textile material, product or article to a second wash in the same machine at a temperature between 20 and 35° C. for a time between 2 and 10 minutes in water, or at 50° C. for a time between 2 and 10 minutes in a solution of sodium acetate in water; 
 5) draining the bath of the second wash and subjecting the textile material, product or article to a color fixing treatment in a bath containing a fixing substance with a percentage between 1% and 6% with respect to the initial weight of the textile material, product or article at a temperature between 20 and 60° C., for a time between 5 and 30 minutes, and at a pH between 4.5 and 6.5 obtained with a pH regulator consisting of a mixture of citric acid and 5-sulfosalicylic acid in a weight ratio between 4:1 and 9:1, and said fixing substance is selected among diethylene glycol, a 5% suspension of silica in water, or a mixture thereof; 
 6) draining the bath and subjecting the textile material, product or article to drying. 
 
     
     
       2. The process according to  claim 1 , further comprising a preliminary step 0 carried out under stirring, wherein said textile material, product or article to be colored is dipped into water at a temperature between 20 and 30° C. for a time between 5 and 10 minutes, and wherein all or part of the quantity of wetting substance necessary for carrying out step 1 is optionally added to water. 
     
     
       3. The process according to  claim 1 , wherein the quantities are used, in percentage by weight with respect to the weight of said textile material, product or article, 1% of said detergent substance, 1% of said wetting substance, between 1% and 2% of said leveling substance and between 10 and 30% of said acidity regulator. 
     
     
       4. The process according to  claim 1 , wherein said one or more synthetic coloring substances are selected from the substances of the following table: 
       
         
           
                 
                 
                 
                 
               
                     
                 
                   Commercial name 
                   CAS No. 
                   Code 
                   Color 
                 
                     
                 
                   Tartrazine - Acid yellow 23 
                   1934-21-0 
                   E102 
                   Yellow 
                 
                   Quinoline yellow 
                   8004-92-0 
                   E104 
                   Yellow 
                 
                   Sunset yellow 
                   2783-94-0 
                   E110 
                   Yellow-orange 
                 
                   Food red 3 
                   3567-69-9 
                   E122 
                   Carmine 
                 
                   Acid red 18 
                   2611-82-7 
                   E124 
                   Red 
                 
                   Erythrosine B - Acid red 51 
                   16423-68-0 
                   E127 
                   Red 
                 
                   Food red 17 
                   25956-17-6 
                   E129 
                   Scarlet red 
                 
                   Amaranth red - Acid red 27 
                   915-67-3 
                   E123 
                   Amaranth red 
                 
                   Food blue 5:2 
                   20262-76-4 
                   E131 
                   Blue 
                 
                   Acid blue 74 
                   860-22-0 
                   E132 
                   Blue 
                 
                   Erioglaucine disodium salt - 
                   3844-45-9 
                   E133 
                   Blue 
                 
                   Food blue 2 
                 
                   Lissamine green B - Acid green 50 
                   3087-16-9 
                   E142 
                   Green 
                 
                   Food black 1 
                   2519-30-4 
                   E151 
                   Black 
                 
                   Chocolate brown HT 
                   4553-89-3 
                   E155 
                   Brown 
                 
                     
                 
             
                
                
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
       5. The process according to  claim 1 , wherein said one or more synthetic coloring substances are used in a quantity between 0.001% and 6% of the weight of the textile product. 
     
     
       6. The process according to  claim 1 , wherein said step 5 is carried out by dipping said textile material, product or article into the bath containing the fixing substance, or with the “foulard” technique when said textile material, product or article is a fabric, or with a spray technique when said textile material, product or article is a finished item of clothing. 
     
     
       7. The process according to  claim 1 , wherein said textile material, product or article is made of wool. 
     
     
       8. A textile material, product or article consisting of animal hair textile fibers, dyed with the textile process according to  claim 1 .